Problems with references to TPL Dataflow and TPL in VS 2012 RC
Solution 1
Try to "Add Reference" the System.Threading.Tasks.dll
explicitly from C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v4.5
. Alternatively you can use C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Facades
directory.
UPDATED: I examined the problem more after reading of the answer about removing the reference to System.Runtime
and I can add the following: The reference to System.Runtime
will be added because of the error in the currect version of NuGet package Microsoft.Tpl.Dataflow.4.5.1-rc
. If one add the reference to the same System.Threading.Tasks.Dataflow.dll
directly in Visual Studio no System.Runtime
reference will be added and no problem exist.
Using NuGet Package Explorer one can download the original Microsoft.Tpl.Dataflow.4.5.1-rc.nupkg
from the "NuGet official package source". At the end of the Package Matadata one will see
One can modify the metadata (press Ctrl-K) and remove the reference:
After that one can save the modified file Microsoft.Tpl.Dataflow.4.5.1-rc.nupkg
in some directory. After adding new location (the local directory) in the list of NuGet sources (see here or here) one will be able to add new package from the local source (don't forget to choose to display all packages inclusive pre-release see the picture below):
The modified Microsoft.Tpl.Dataflow.4.5.1-rc.nupkg
will not add System.Runtime
and the project will be compiled without errors.
So the bug exist not in Visual Studio 2012 RC and even not in Microsoft.Tpl.Dataflow.dll
. The bug is just in the metadata of the pre-release version of Microsoft.Tpl.Dataflow
NuGet package available currently on "NuGet official package source".
You can post the bug report to the autors so that the package will be fixed.
UPDATED 2: Even if my answer are already marked as solved and the bounty awarded the problem still not go from my head. In reality I see two opened problems:
- Why the existence of unused assembly
System.Runtime
can produce the error during the builging of the project. - I see some general problems in the way how Uninstall or Update of NuGet packages works (see details later).
Let us we accept just the fact that the first problem exist independent from the reason. The second problem make me restlessness. I see the real problem here. Everybody can make the following experiment to understand me better:
- Create a new empty console application in Visual Studio 2012 RC.
- Verify that the project has no reference to
System.Runtime
. - Open "Package Manager Console" from "Tools" / "Library Package Manager".
- Execute the command "Install-Package Microsoft.Tpl.Dataflow -Pre" in the "Package Manager Console".
- Verify that both
System.Runtime
andSystem.Threading.Tasks.Dataflow
are included in the list of References of the project. - Execute the command "Uninstall-Package Microsoft.Tpl.Dataflow" in the "Package Manager Console".
- Verify that
System.Threading.Tasks.Dataflow
are removed from the list of References of the project, butSystem.Runtime
is still in the list of references.
I made one more experiment and I changed the version of modified Microsoft.Tpl.Dataflow.4.5.1-rc.nupkg
, where I removed the reference to System.Runtime
, from 4.5.1-rc
to 4.5.1-rc1
and saved it locally (it will be saved under Microsoft.Tpl.Dataflow.4.5.1-rc1.nupkg
). After that I could see "new" version in the list of Updates to my project:
If I install the Update the reference to System.Runtime
will be also not removed.
So the current implementation of "Update" and "Uninstall" of NuGet has the bug or general design problem. If we added a package to our project and make some updates of the project we will get references of all dependent assemblies of all old versions. The old references, added by NuGet from old versions of the package, will be not removed during Uninstall or Update. First of all it's not good itself to have garbage in the project references, but because of existence the first problem (error during compilation if the reference to unreferenced System.Runtime
exist) the problem will be even more serious.
So if nothing will be changed in NuGet the update to the next version of Microsoft.Tpl.Dataflow
will not solve the problem for the users who installed Microsoft.Tpl.Dataflow
in version 4.5.1 (or probably early version). All users will have to remove the reference to System.Runtime
manually. I think that it's real NuGet problem which have to be solved by NuGet developers. I will post the description of the problem to http://nuget.org/ later.
The bug report which I posted to NuGet can be found here (sorry for not perfect formatting of the text).
Solution 2
According to Alok Shriram from MS, the solution is to remove the reference to System.Runtime, and that this will be fixed in the next release.
I can confirm that removing the reference actually fixes the issue.
svick
Updated on June 05, 2022Comments
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svick over 1 year
I just upgraded Visual Studio 11 Beta to the new Visual Studio 2012 RC and have problems referencing TPL Dataflow.
First, I tried to reference Dataflow as I did previously, by adding a reference from the framework. But when I try to do that, I get an error box:
A reference to 'System.Threading.Tasks.Dataflow' could not be added.
and then the whole Visual Studio freezes.
After reading MEF and TPL Dataflow NuGet Packages for .NET Framework 4.5 RC, I assumed the version of Dataflow that showed in the references list was some kind of artifact of the previous installation. So, I tried using Dataflow from NuGet, which seemed to work, until I actually tried to compile my code, because I got an error:
The type 'System.Threading.Tasks.Task' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Threading.Tasks, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
This is confusing, because
Task
is in mscorlib, no other references should be necessary. But there is a reference assembly calledSystem.Threading.Tasks
in the references list, so I tried to add that. Unfortunately, a familiar error showed:A reference to 'System.Threading.Tasks' could not be added.
and then Visual Studio froze again.
Am I doing something wrong? How can I use TPL Dataflow with VS 2012 RC?
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svick over 11 yearsThanks, that seems to work (I used the second one). Any idea why this happens?
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Oleg over 11 years@svick: I don't examined the problem in details. Without the reference the new version of
System.Threading.Tasks.Dataflow
tried to use wrong version ofSystem.Threading.Tasks.dll
. I don't used TPL Dataflow before. I just copied the demo code from the page and get the error which you described and the error in the lineworkerBlock.Completion.Wait();
: Wait method is not exist. It was clear that Microsoft changed some classes and I used wrong assembly. So one needed only to find the correct one. -
Oleg over 11 years@svick: By the way I found at the end of the blog the tip to add the same reference as I descried in my answer. So it seems that you are not the first person who has the problem.
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Oleg over 11 yearsRemoving of the reference to
System.Runtime.dll
from the project is better as to add new referenceSystem.Threading.Tasks.dll
. From the other side it don't really clear why the conflict exist. I examined the Manifest ofSystem.Runtime.dll
with respect of "IL Disassembler" (ildasm.exe) and could not see any conflicts. So for me both ways are like: "Do this and the problem will be solved". So I can repeat the same question which you asked me first: "Any idea why this happens?" -
svick over 11 yearsYeah, I'd like to know too. SR doesn't contain any AssemblyRef to STT, so I have no idea why does removing it help.
-
Oleg over 11 yearsMoreover, the reference to
System.Runtime
was added by the executing ofInstall-Package Microsoft.Tpl.Dataflow -Pre
, but fhe filesystem.threading.tasks.dataflow.xml
don't contain anySystem.Runtime
text. If we would have some assembly loading problems we could use Fuslogvw.exe for tracing, but we have compiler error. By the way I used ReSharper which help to removed unused references, but it don't removedSystem.Runtime
like other references. -
Oleg over 11 yearsBy the way if one remove both references and then add manually
.\packages\Microsoft.Tpl.Dataflow.4.5.1-rc\lib\net45\System.Threading.Tasks.Dataflow.dll
the second dll (System.Runtime.dll
) will be not added. So I suppose that the reason can be more in the NuGet package. I examined it with respect of NuGet Package Explorer, but one can't see directly any reference toSystem.Runtime.dll
(at least in GUI of NuGet Package Explorer). So the problem is still not full clear for me. -
Oleg over 11 yearsOh I was not carefully enough. The NuGet Package Explorer do shows that
Microsoft.Tpl.Dataflow
requireSystem.Runtime.dll
. In the Package metadata under "Framework Assembly References" one see "System.Runtime". So at least the part of the origin of the problem:Microsoft.Tpl.Dataflow.4.5.1-rc.nupkg
contains the reference toSystem.Runtime.dll
which is wrong. -
svick over 11 yearsThanks for the details. I don't think notifying the authors of the NuGet package is necessary, since Alok Shriram, who is listed among the owners of that package, is the one who responded on social.msdn with the System.Runtime fix and said that it will be fixed in the next release (not sure whether he meant next release of the package or of Visual Studio).
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Oleg over 11 years@svick: You are welcome! I understood the answer of Alok Shriram more as the error exist in Visual Studio 2012 RC, because he emphasized that the problem exist especially in RC. Probably I misunderstood the answer, but it was not so clear. In any way fixing one element of small XML metadata file and publishing on the NuGet online is really easy. I don't understand why one should wait for some "next release".
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Oleg over 11 years@svick: I write one more "UPDATE" to my answer where I described one more important problem which I still see in NuGet Update/Uninstall.
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svick over 11 yearsTurns out, we didn't have to wait long for that release. I can confirm that the updated NuGet package works correctly (it doesn't add reference to System.Runtime).
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Oleg over 11 years@svick: It's very good news. The new 4.5.4-rc version has no referenced to unused assembly
System.Runtime
. I am sure that it will help other users of the package. About my bug report to NuGet developers I don't found understanding of the problem. Many year ago I spend many my time to software deployment. I see the problem which I posted to NuGet as serious design problem, but I don't wont to sent my time now with long discussion in comments to the bug report. I reported. One see no problem. OK. In any way your question was interesting for me. -
Nicholas Blumhardt over 11 yearsWe've posted version 4.5.4-rc of the NuGet package to fix this issue.
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digiogo about 8 yearsThe step "Add Reference to the System.Threading.Tasks.dll" helped me to solve the same issue in a similar issue: .Net 4.6 Roslyn compiler wasn't recognizing a Task<> return inside a Portable Class Library (PCL) referenced in my project.
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Oleg about 8 years@digiogo: You are welcome! I'm glad to know that the old answer is still helpful for some cases.